The present invention relates to an instrument base for optical devices, such as ophthalmological or intravital microscopic instruments, and more particularly to such an instrument base having a horizontally displaceable base plate and a horizontally rotatable instrument carrier, which is adjustable in height and is arranged above the base plate.
Instrument bases for optical devices and, in particular, for ophthalmological examining instruments are known in different design forms. The construction of such instrument bases is determined essentially by the size and the weight of the structural parts to be mounted on them and by the precision and versatility of possible settings. The accurate optical and geometrical adjustability of the instrument to the object to be examined is an absolute requirement. This is particularly true when optical structural elements are to be placed in direct contact with the organ to be examined.
A typical example for an arrangement of this type is an instrument for the examination of frontal sections of the eye, such as for example the epithelium or endothelium of the cornea at higher magnifications. In the process, in order to achieve optical results, it is often impossible to avoid a direct contact of the eye to be examined with an objective lens or an adapter lens which is separate from the objective lens.
In addition to coarse focusing and the feasibility of quickly changing positions on the eye to be examined, in this case there should also be possible a subsequent fine focusing and fine adjustment in the direction of the X-Y coordinates, as well as an adjustability of the contact lens in the horizontal and vertical directions independently of the overall settings of the instrument base.
In DL-P No. 60,443 is disclosed a device for the fine adjustment of ophthalmological instruments, having a lever rotatable in all directions in the horizontal plane for setting purposes, and a spindle equipped with threads and engaging a hub for adjustments in height. The lever is rotatable about its longitudinal axis and is connected both with the lever and with the hub. In this manner, the lever may be used both for horizontal and vertical adjustment. Examinations with stronger magnification in the micro range, as is frequently required, for example, in relation to the epithelium or endothelium of the cornea and direct contact with the eye being examined are not feasible with this arrangement.
The same is true for the arrangement known from DE-AS No. 1,189,759 which includes an illumination and observation device rotatable around a vertical axis, whereby the latter is also rotatable around an axis which passes through the eye to be examined and which stands perpendicular to the direction of the observation. In this manner, details particularly in the upper and lower parts of the frontal regions of the eye may be observed well, but because of the variable height and inclination of the viewing direction, the arrangement is inconvenient.
DE-OS No. 2,520,445 discloses an arrangement for the examination of the eye having a microscope mounted on a support arm, wherein the support arm may be rotated around a swivel axis. A thumb lever, a knurled knob and a rotatable finger are provided for adjustment. Direct contacting is again not possible with this device. Furthermore, the device is not suitable for use with micro objectives having strong inherent magnification or for distortion-free image reproduction in photographic recording, because of its low stability.
Other known devices provide rapid adjustments in the horizontal and vertical planes with adequate accuracy but are not designed for either horizontal or vertical rotation or cannot be readjusted from vertical to oblique observation. Particularly in the examination of the endothelial cell structure at the rear side of the cornea, such an adjustment is especially advantageous by making possible observations at the angle of reflection of the light incident on the object plane.